Susceptibility of mice to sexual transmission of LP-BM5 is dependent on mA3 expressed in genitalia. Age and weight-matched mA3-/- male (♂) mice on C57BL/6 background (n = 6) were lethally irradiated, reconstituted with bone marrow stem cells from WT or mA3 -/- mice, infected with LP-BM5 virus, and mated with naïve WT females (♀) for six days. Male mice were sacrificed at the end of mating. Female mice were allowed to nurse the resultant off-springs (heterozygotes) for three weeks. Off-springs were divided into two groups, and the first group were sacrificed at four week and the second group at thirteen weeks post-parturition (A). Spleen, testes, epididymis, and seminal gland were obtained from male mice and used for DNA extraction and examination of infection level by qPCR (B to E). Spleen and mammary gland tissues were obtained from female mice and used to evaluate rate of virus transmission by qPCR (F and G). Spleen tissues from the off-springs were used to examine rate of virus transmission from the infected mother (H and I). Error bars are standard error; ** is significance with p value equal or less than 0.01. This experiment was repeated 2 additional times with similar results. ♂ = male, ♀ = female.